:root{--bg:#f5f7fa;--card:#fff;--ink:#14202d;--muted:#596577;--line:#dfe4ea;--accent:#0f4c81;--accent2:#1c6aa8;--soft:#eaf1f8;--warn:#8a5a00;--warnbg:#fff6e0}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){--bg:#0e1319;--card:#151c24;--ink:#e5eaf0;--muted:#9aa6b4;--line:#26313d;--accent:#6aa7dc;--accent2:#4f8fc8;--soft:#1a2633;--warn:#f0c46a;--warnbg:#2a2312}}
:root[data-theme="dark"]{--bg:#0e1319;--card:#151c24;--ink:#e5eaf0;--muted:#9aa6b4;--line:#26313d;--accent:#6aa7dc;--accent2:#4f8fc8;--soft:#1a2633;--warn:#f0c46a;--warnbg:#2a2312}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:17px/1.7 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif}
a{color:var(--accent)}
.wrap{max-width:1080px;margin:0 auto;padding:0 16px}
header{background:var(--card);border-bottom:1px solid var(--line);position:sticky;top:0;z-index:5}
header .wrap{display:flex;align-items:center;justify-content:space-between;gap:12px;padding-top:14px;padding-bottom:14px;flex-wrap:wrap}
.brand{font-weight:700;letter-spacing:.06em;text-transform:uppercase;font-size:15px;color:var(--ink);text-decoration:none;display:flex;align-items:center;gap:10px}
.brand svg{flex:none}
.brand small{display:block;font-weight:400;letter-spacing:0;text-transform:none;color:var(--muted);font-size:12.5px}
nav{display:flex;flex-wrap:wrap;gap:4px 18px}
nav a{color:var(--ink);text-decoration:none;font-size:15px;padding:2px 0;border-bottom:2px solid transparent}
nav a:hover,nav a.on{color:var(--accent);border-bottom-color:var(--accent)}
.hero{background:linear-gradient(135deg,#0b3a63,#0f4c81 45%,#1c6aa8);color:#fff;padding:72px 0 64px}
.hero.small{padding:44px 0 38px}
.hero h1{font-size:clamp(28px,5vw,46px);line-height:1.15;margin:0 0 12px;max-width:18em}
.hero.small h1{font-size:clamp(26px,4vw,38px)}
.hero p{margin:0;max-width:40em;opacity:.93;font-size:18px}
.hero .cta{display:inline-block;margin-top:24px;background:#fff;color:#0f4c81;padding:10px 20px;border-radius:8px;text-decoration:none;font-weight:600;margin-right:10px}
.hero .cta.ghost{background:transparent;color:#fff;border:1px solid rgba(255,255,255,.6)}
.crumbs{font-size:14px;opacity:.85;margin-bottom:8px}
.crumbs a{color:#fff}
main.wrap{padding-top:36px;padding-bottom:28px}
.layout{display:grid;grid-template-columns:minmax(0,1fr) 280px;gap:28px;align-items:start}
@media (max-width:860px){.layout{grid-template-columns:minmax(0,1fr)}}
section,article,aside .box{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:28px;margin-bottom:24px}
article h2{margin:30px 0 8px;font-size:23px}
article h2:first-child{margin-top:0}
article h3{margin:22px 0 6px;font-size:18.5px}
h2{margin:0 0 10px;font-size:23px}
p{margin:0 0 14px}
ul,ol{margin:0 0 14px;padding-left:22px}
li{margin-bottom:6px}
table{width:100%;border-collapse:collapse;margin:6px 0 18px;font-size:15.5px;display:block;overflow-x:auto}
th,td{text-align:left;padding:9px 10px;border-bottom:1px solid var(--line);vertical-align:top}
th{background:var(--soft)}
.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:16px}
.card{border:1px solid var(--line);border-radius:10px;padding:18px;background:var(--card)}
.card h3{margin:0 0 6px;font-size:17.5px}
.card h3 a{text-decoration:none}
.card p{margin:0;color:var(--muted);font-size:15.5px}
.tag{display:inline-block;font-size:12.5px;text-transform:uppercase;letter-spacing:.05em;color:var(--accent);margin-bottom:4px}
.note{background:var(--warnbg);color:var(--ink);border-left:4px solid var(--warn);padding:14px 16px;border-radius:6px;font-size:15.5px;margin:18px 0}
.key{background:var(--soft);border-radius:10px;padding:16px 18px;margin:18px 0}
.key strong{display:block;margin-bottom:4px}
.formula{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;background:var(--soft);padding:10px 14px;border-radius:8px;overflow-x:auto;white-space:pre-wrap;font-size:15px;margin:0 0 14px}
aside .box{padding:20px}
aside h4{margin:0 0 8px;font-size:15px;text-transform:uppercase;letter-spacing:.05em;color:var(--muted)}
aside ul{list-style:none;padding:0;margin:0}
aside li{margin:0;border-bottom:1px solid var(--line)}
aside li:last-child{border-bottom:0}
aside li a{display:block;padding:7px 0;text-decoration:none;font-size:15px}
aside li a.on{font-weight:600}
.pager{display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap;margin-top:8px}
.pager a{text-decoration:none;border:1px solid var(--line);border-radius:8px;padding:10px 14px;background:var(--card);max-width:48%}
.pager small{display:block;color:var(--muted)}
dl dt{font-weight:700;margin-top:14px}
dl dd{margin:2px 0 0 0;color:var(--ink)}
.letters{display:flex;flex-wrap:wrap;gap:6px;margin-bottom:10px}
.letters a{text-decoration:none;border:1px solid var(--line);border-radius:6px;padding:2px 9px;font-size:14px}
details{border:1px solid var(--line);border-radius:10px;padding:12px 16px;margin-bottom:10px;background:var(--card)}
details summary{cursor:pointer;font-weight:600}
details p{margin:10px 0 0}
.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:14px;margin-top:4px}
.stats div{background:var(--soft);border-radius:10px;padding:16px}
.stats b{display:block;font-size:22px;color:var(--accent)}
footer{background:var(--card);border-top:1px solid var(--line);padding:32px 0 40px;color:var(--muted);font-size:14.5px;margin-top:20px}
footer .cols{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:20px;margin-bottom:20px}
footer h5{margin:0 0 8px;font-size:14px;color:var(--ink);text-transform:uppercase;letter-spacing:.05em}
footer a{color:var(--muted);text-decoration:none;display:block;padding:2px 0}
footer a:hover{color:var(--accent)}
@media (max-width:600px){.hero{padding:48px 0 40px}section,article{padding:20px}.pager a{max-width:100%;flex:1 1 100%}}